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Biomedical subjects

R K Parrish

Publications and source records attributed to R K Parrish.

At least 37 records · Page 2Linked to original sources
PubMed1995

Open-angle glaucoma after pars plicata lensectomy and vitrectomy for congenital cataracts.

PURPOSE/METHODS: We examined an infant with familial cataracts in whom bilateral open-angle glaucoma developed shortly after pars plicata lensectomy with anterior vitrectomy. RESULTS/CONCLUSIONS: Some eyes with congenital nuclear cataracts have a predisposition to develop glaucoma after removal of the cataract, which is irrespective of the method chosen to remove the cataract. Careful monitoring of the intraocular pressure is indicated.

Cataract↗
PubMed1995

5-Fluorouracil filtering surgery and neovascular glaucoma. Long-term follow-up of the original pilot study.

BACKGROUND: The long-term efficacy and safety of filtering surgery with 5-fluorouracil (5-FU) in eyes with neovascular glaucoma are unknown. METHODS: Kaplan-Meier survival curve analysis of surgical outcome was performed on all 34 patients (34 eyes) enrolled from May 1982 through April 1986 in the original pilot study of filtering surgery with 5-FU. RESULTS: Success rates at the 1-, 2-, 3-, 4-, and 5-year intervals were 71%, 67%, 61%, 41%, and 28%, respectively. The median filter survival time was 38.7 months (95% confidence interval: 32-45 months). Twelve (35%) of 34 patients lost light perception vision, and phthisis bulbi developed in 8 (24%) of 34 patients. Age of 50 years or younger (P < 0.0001) and type 1 diabetes (P = 0.0004) were significant risk factors for surgical failure. The 1-year success rate for patients no older than 50 years of age was 23% compared with a 95% success rate in patients older than 50 years of age. After adjustment for age, type 1 diabetes was a borderline risk factor (P = 0.06). CONCLUSION: There is a high risk of long-term failure of filtering surgery with 5-FU in neovascular glaucoma. Patients 50 years of age or younger have an extremely poor prognosis. Patients older than 50 years of age have initial short-term success with an accelerated failure rate after 3 years.

Adolescent↗
PubMed1993

Strabismus following implantation of Baerveldt drainage devices.

OBJECTIVE: To describe the clinical features of strabismus following implantation of a Baerveldt glaucoma seton. DESIGN: Case series of four patients with a minimum follow-up of 6 months. SETTING: Specialized glaucoma referral center at Bascom Palmer Eye Institute/Ann Bates Leach Eye Hospital, Miami, Fla. PATIENTS: Consecutive sample of four patients with persistent binocular diplopia following implantation of a 350-mm2 Baerveldt glaucoma seton in the superotemporal quadrant. RESULTS: Each patient presented with a characteristic pattern of either exotropia or hypertropia, or both. The deviation increased with gaze opposite the ipsilateral superior and lateral muscles and decreased in the field of action of the involved muscles. All patients demonstrated a convergence insufficiency type of exotropia. CONCLUSION: These patients presented with a similar type of restrictive strabismus. Proposed mechanisms include an increase in the length-tension curve of the muscle induced by the underlying bleb and a posterior fixation effect as a result of scarring behind the implant.

Aged↗
PubMed1991

5-Fluorouracil after trabeculectomy and the iridocorneal endothelial syndrome.

Nine patients (nine eyes) with iridocorneal endothelial (ICE) syndrome underwent trabeculectomy and received postoperative subconjunctival injections of 5-fluorouracil (5-FU) to enhance bleb formation (total 5-FU dose, 30-105 mg; mean, 53.8 mg). Eight eyes had undergone prior unsuccessful trabeculectomy. Four eyes had intraocular pressure (IOP) less than or equal to 21 mmHg on zero to two glaucoma medications after 6 to 54 months of follow-up (mean, 25.3 months). Five eyes required repeat surgery within 2 to 13 months and were considered failures. All five eyes that failed received a Molteno drainage implant. Progressive endothelial proliferation may explain late onset bleb failure and the relative ineffectiveness of 5-FU in this condition.

Adult↗
PubMed1990

Contact B-scan echography in the assessment of optic nerve cupping.

We determined the reliability of high-resolution contact B-scan echography for estimating the optic cup size in 56 eyes of 28 patients with glaucoma or ocular hypertension. Two trained observers independently evaluated horizontal and vertical cup/disk ratios in stereophotographs, and two skilled echographers independently estimated optic cup size in photoechograms in a masked fashion. The reliability of echographic interpretation varied (kappa 0.29 to 0.71), but it always exceeded that expected by chance alone, even for cups of 0.3 disk diameter or less. Subtly saucer-shaped cups (three of 50 eyes) and deep cups with intact neuroretinal rims (two of 50 eyes) were misinterpreted echographically. High-resolution contact B-scan echography may provide a useful and reliable estimate of the optic cup size in eyes with opaque media.

Fundus Oculi↗
PubMed1990

A prospective study of angiographic cystoid macular edema one year after Nd: YAG posterior capsulotomy.

We prospectively studied 120 eyes with intact opacified posterior capsules in 120 consecutive patients to determine the incidence of new late-onset angiographic cystoid macular edema (CME) after neodynium: yttrium aluminum garnet (Nd:YAG) laser posterior capsulotomy. Fifty-seven of 120 patients (48%) had both precapsulotomy and one-year post-capsulotomy angiograms done. Of these 57 patients, three eyes had angiographic CME before capsulotomy and two of these three cases had persistent CME one year after capsulotomy. In the other 54 patients, three new late-onset cases occurred (5.6%). Because the incidence of postcapsulotomy new CME was low, the statistical significance of possible risk factors, such as rupture of the anterior hyaloid face or pseudophakic status cannot be determined. However, aphakic patients with vitreous prolapse after capsulotomy tended to have a higher incidence to CME than pseudophakic patients. We recommend fluorescein angiography to identify occult CME in cases of unexplained visual-acuity decrease after capsulotomy.

Aged↗
PubMed1987

Noncontact trephination of the cornea using a pulsed hydrogen fluoride laser.

We used a pulsed hydrogen fluoride infrared laser and a specially designed axicon lens to perform circular corneal trephinations in ten eye bank eyes. This noncontact system focused each laser pulse into an annulus on the cornea. Corneal perforation was achieved in seven to nine seconds at a repetition rate of 10 Hz, using a laser output energy of 100 mJ per pulse. A trephination, 90% of corneal thickness, 6.5 mm in diameter, was produced with 70 pulses.

Cornea↗
PubMed1987

Zonular dialysis during extracapsular cataract extraction in pseudoexfoliation syndrome.

Five patients with pseudoexfoliation syndrome (PES) and glaucoma developed extensive zonular dialyses during extracapsular cataract extractions. Weakness of the lens zonules or their attachments to the ciliary processes, which has been described in association with PES, may explain this complication. We believe that patients with PES are at particular risk for developing large zonular dialyses during extracapsular surgery. Preoperative phakodonesis, anterior chamber depth asymmetry, and excessive lens movement during the anterior capsulotomy should alert the surgeon to this problem.

Aged↗
PubMed1987

Glaucoma filtering surgery with 5-fluorouracil.

A life-table analysis of surgical outcomes was performed on the first eye of 155 patients who were enrolled in a pilot study of glaucoma filtering surgery with postoperative subconjunctival 5-fluorouracil (5-FU) injections. The success rates at 1-, 2-, and 3-year intervals were 68, 63, and 63%, respectively, for 88 patients with non-neovascular glaucoma in aphakia; 82, 75, and 75% for 39 patients with non-neovascular glaucoma after unsuccessful filtering surgery; and 68% at each yearly interval for 28 patients with neovascular glaucoma. Complications which resulted from filtering surgery and the 5-FU injections included corneal epithelial defects (55.5%), conjunctival wound leaks (36.8%), suprachoroidal hemorrhage (5.8%), rhegmatogenous retinal detachment (2.6%), endophthalmitis and phthisis (1.9% each), and corneal scarring, late bleb leak, malignant glaucoma, and traction retinal detachment (1.3% each). A Cox Model regression analysis failed to demonstrate a correlation between surgical success and age, race, type of filtering procedure, or total dose of 5-FU received. Postoperative subconjunctival 5-FU may increase the operative success rate for selected patients with a high risk for failure after glaucoma filtering surgery.

Actuarial Analysis↗
PubMed1987

Mutagenic potential of a 193-nm excimer laser on fibroblasts in tissue culture.

In response to concerns regarding possible DNA damage by far ultraviolet radiation during excimer laser corneal surgery, the mutagenic potential of an argon fluoride excimer laser (193 nm) on BALB/3T3 mouse fibroblasts grown in tissue culture was investigated. The cumulative incidence of anaplastic transformation after subablative radiant exposures from 3.5 mJ/cm2/pulse to 13.4 mJ/cm2/pulse was 3.6% of all cell cultures. The incidence of anaplastic transformation in nonirradiated controls was 4.2%. Transformation after exposure to x-ray radiation (60.9 rad) was 98.8%. The difference between the incidence of transformation of nonirradiated controls or excimer-treated cultures compared with x-ray radiation-treated cells was significant P less than 0.0001 (chi square test). In this standard cell line, 193-nm laser energy does not appear to have substantial mutagenic potential.

Anaplasia↗